Hydrocarbons may be difficult to purge from hydrocarbon storage canisters of HEVs during periods when the engine of the HEV is not being operated. Evaporative regulations may require that the hydrocarbon storage canister of HEVs be saturated with hydrocarbon prior to testing. Regulatory requirements may require purging of the hydrocarbon storage canister prior to diurnal testing.
Therefore, a hydrocarbon storage canister purge system and method are needed which are capable of determining the concentration of hydrocarbons in the canister outlet vent area of a hydrocarbon storage canister and purging the hydrocarbons from the hydrocarbon storage canister.